Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• electrosynthesis was conducted in a microreactor equipped with two Pt electrodes as the anode and cathode and operated with a constant current (Table 1). Under the optimized conditions, a solution of tetrahydroisoquinoline 1a (1 equiv), alkyne 2 (1.5 equiv), Cu(OTf)2 (10 mol %), TEMPO (20 mol %), n-Bu4NPF6 (0.2

• oxoammonium salt TEMPO+ [50][51], which reacts with tetrahydroisoquinoline 23 to generate TEMPOH and iminium ion 24 [52], TEMPOH is oxidized back to TEMPO+ on the anode. On the other hand, 24 is converted to the final product 25 through reaction with copper acetylide 26, which is generated from CuI and the

• scope. Reaction conditions: Pt anode, Pt cathode, interelectrode distance 0.25 mm, 1 (0.03 M, 0.21 mmol), 2 (0.045 M, 1.5 equiv), Cu(OTf)2 (10 mol %), TEMPO (20 mol %), n-Bu4NPF6 (20 mol %), TFE (3.5 equiv), MeCN (7 mL), I = 30 mA, flow rate = 0.20 mL min−1, rt. Isolated yields are reported. Reaction

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• µm i.d. uncoated bare fused capillary, HR-NCHO separation gel buffer (Sciex). The applied electric field strength was 1500 V/cm with the cathode at the injection side and the anode at the detection side (reversed polarity). Samples were electrokinetically injected using 1kV for 5 s. For migration

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• Rigaku FRX® high flux rotating anode with a Pilatus 200K hybrid pixel detector. Using Olex2 [27], the structure was solved with the ShelXT [28] structure solution program using Intrinsic Phasing and refined with the ShelXL [29] refinement package using the full least-squares correlation matrix. The non

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• ; anal. calcd for C29H14O2(H2O)0.4: C, 86.73%; H, 3.71%; found: C, 86.58%; H, 3.50%. Single crystal X-ray analysis The diffraction data for 5a and 5c were collected on a Rigaku FR-E Superbright rotating-anode X-ray source with a Mo-target (λ = 0.71073 Å) equipped with a Rigaku RAXIS VII imaging plate as

Six-fold C–H borylation of hexa-peri-hexabenzocoronene

• Mai Nagase,
• Kenta Kato,
• Akiko Yagi,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2020, 16, 391–397, doi:10.3762/bjoc.16.37

• rotating anode (Graphite-monochromated Mo Kα radiation (λ = 0.71073 Å)) and PILATUS200K hybrid photon-counting detector. Cell parameters were determined and refined, and raw frame data were integrated using CrysAlisPro (Agilent Technologies, 2010). The structures were solved by direct methods with (SHELXT

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• developed an electrochemical approach for a Sharpless asymmetric dihydrohydroxylation of alkenes using an osmium complex [63]. In this protocol, the traditional chemical oxidant was replaced by an anode that regenerates [FeCN)6]3− via an Os(VIII) to Os(VI) interconversion. Similarly, Torri and co-workers

• ). Constant current electrolysis of 89 in a single compartment cell using a sacrificial Mg anode was conducted in the presence of a Ni catalyst and chiral ligand 90. After esterification and purification, 91 was isolated in a good yield and with moderate enantioselectivity [70]. In another recent report, Guo

• methyl sulfide using chemically modified graphite anode. Asymmetric oxidation of unsymmetric sulfides using poly(amino acid)-coated electrodes. Enantioselective, electocatalytic oxidative coupling on TEMPO-modified graphite felt electrode in the presence of (−)-sparteine. Asymmetric electrocatalytic

A diastereoselective approach to axially chiral biaryls via electrochemically enabled cyclization cascade

• Hong Yan,
• Zhong-Yi Mao,
• Zhong-Wei Hou,
• Jinshuai Song and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2019, 15, 795–800, doi:10.3762/bjoc.15.76

• previously established conditions employing a three-necked round-bottomed flask as the cell, a reticulated vitreous carbon (RVC) anode and a platinum plate cathode [31]. The reaction was carried in refluxing MeCN/H2O (9:1) with tetraarylhydrazine 1 as the redox catalyst, NaHCO3 (2 equiv) as an additive, and

• reaction. A mechanism for the electrochemical synthesis was proposed based on the results from our previous work [31] and of this work (Scheme 3). The redox catalyst 1 is oxidized at the anode to give radical cation I. In the meanwhile, H2O is reduced at the cathode to afford HO− and H2. The base generated

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• complex and the oxidation of the Co(III)-dialkylated complex proceeded at the cathode and anode, respectively [61]. These processes were coupled to achieve the 1,2-migration of functional groups. Further investigations with diethyl 2-bromomethyl-2-phenylmalonate as a substrate confirmed that the

• carboxylic ester-migrated product was formed via not a radical, but a cationic intermediate that was generated by the fragmentation to the monoalkylated complex at the anode (Scheme 2). 2-2. Artificial enzyme-mediated reactions A vesicle-type B12 artificial enzyme was constructed by combining bilayer

• first time through electrolysis under non-enzymatic conditions. The methyl transfer from TsOCH3 to 1-octanethiol was mediated by controlled-potential electrolysis at −1.0 V vs Ag/AgCl in the presence of 1 at 50 °C (Scheme 6b) [75]. The Zn plate was used as a sacrificial anode and the resultant Zn2+ ions

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• linear sweep voltammetry (LSV). For this, we chose complexes 1-CN, 1-H and 1-OMe to include ligand substitutions with electron-withdrawing and electron-donating properties (Figure 4). In Figure 4a, an abrupt onset of the catalytic anode current at 0.7 V, 1.0 V and 1.3 V for 1-CN, 1-H and 1-OMe is

Direct electrochemical generation of organic carbonates by dehydrogenative coupling

• Tile Gieshoff,
• Vinh Trieu,
• Jan Heijl and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2018, 14, 1578–1582, doi:10.3762/bjoc.14.135

• reactive chemicals. We present the first direct electrochemical generation of mesityl methyl carbonate by C–H activation. Although this reaction pathway is still challenging concerning scope and efficiency, it outlines a new strategy for carbonate generation. Keywords: anode; boron-doped diamond

• diamond (BDD) as electrode material has the capability to convert simple aromatic systems by direct C–H activation [21][22][23][24][25][26][27]. In contrast, other typical anode materials such as graphite, glassy carbon, or platinum tend to lead to electrode fouling when applying high positive potentials

• . Within our studies, we observed that only acetonitrile as solvent and BDD as anode material led to a successful conversion. Other electrodes and solvents (see Supporting Information File 1) indicated no traces of product in accordance with the high potential range accessible with this electrolyte

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• with the same electrode. Electrolysis of HMF using a CoB modified nickel foam electrode at 1.45 V vs RHE achieved close to 100% selective conversion of HMF to FDCA at 100% faradaic efficiency. Keywords: alternative anode reaction; electrocatalysis; electrosynthesis; HMF oxidation; hydrogen evolution

• comparatively low economic value with respect to the energy demand of its production. Thus, replacing the OER by a thermodynamically and/or kinetically more favorable anode reaction is desirable in order to increase the energy efficiency of the hydrogen production and hence to facilitate the development of

• large scale electrochemical hydrogen production. Advantageously, the oxidation of an alternative substrate at the anode, for example a biomass-derived fuel, allows to generate high value products besides hydrogen concomitantly with an increase in energy conversion efficiency during electrolysis [4

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• of 1.1 V and 1.4 V, respectively, probably due to a fast diffusion of 3 and 4 to the anode in the beam path (Figure 4, Figures S11–S14, Supporting Information File 1). In addition, precipitation of some poorly soluble [4][X] also occurs. During oxidation to the respective ferrocenium cations, the C=O

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• experiments were carried out in a divided glass cell separated through a porous glass plug filled with a layer of gel (i.e., methyl cellulose 0.5 vol % dissolved in DMF/Et4NBF4, 1.0 mol dm−3). Pt spirals (apparent area 0.8 cm2) were used as both cathode and anode, unless otherwise specified. Catholyte: 5 mL

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• with the functional function of the anode ITO (−4.5 to −5.0 eV). The LUMO energy levels of CEPDO and CBPDO are estimated from the half-potential to be −2.31 eV and −2.32 eV, respectively, which are matched with the LUMO energy level of electron injection material TAZ and favorable for electron

Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis

• Tatiana Golub and
• James Y. Becker

Beilstein J. Org. Chem. 2018, 14, 861–868, doi:10.3762/bjoc.14.72

• RCONHCH2OCH3. Moreover, upon replacing LiClO4 with Et4NBF4 an additional fragmentation type of product was generated from the latter amides, namely RCONHCHO. Also, the anodic process was found to be more efficient with C felt as the anode, and in a mixture of 1:1 methanol/acetonitrile co-solvents. Keywords

• the N atom. It was also found that the relative ratio among products was strongly dependent on the nature of the supporting electrolyte, the anode material and the substituent group attached to the N atom. Amides and polyamides have been found as key units in many biologically active and

• properties of α,ω-bisamides derived from α,ω-diaminoalkanes. However, notably that the bisamide 3,5-diaza-2,6-heptanedione was obtained from N-methylacetamide by electrolysis on a Pt anode in water [20]. The present work describes the electrochemical behavior of eight synthesized bisamides (from diamines

Electrochemical Corey–Winter reaction. Reduction of thiocarbonates in aqueous methanol media and application to the synthesis of a naturally occurring α-pyrone

• Ernesto Emmanuel López-López,
• José Alvano Pérez-Bautista,
• Fernando Sartillo-Piscil and
• Bernardo A. Frontana-Uribe

Beilstein J. Org. Chem. 2018, 14, 547–552, doi:10.3762/bjoc.14.41

• first reduction peak observed in cyclic voltammetry (−1.45V vs Ag/AgCl) in a divided (sintered glass) H-type cell fitted with a reticulated vitreous carbon cathode and a stainless steel anode (see Supporting Information File 1 for details). When 2.2 F/mol were consumed (ca. 1.5 h), TLC control of the

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (LPd) of 0.2 and 0.02 mg cm−2. The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was

• advantages compared to the use of conventional electrochemical reactors, as follows: i) nanostructurated electrocatalysts can be utilized for both cathodic and anodic reactions, ii) a solid polymer electrolyte is used instead of a conventional electrolyte and iii) a decrease of the anode–cathode gap reduces

• electrode for the hydrogen oxidation reaction. Moreover, in the absence of an acid medium as supporting electrolyte commonly used at the cathode compartment, the electrocatalytic hydrogenation is feasible by the sole supply of hydronium ions generated at the anode compartment coming from the hydrogen

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• -trimethoxybenzene (2a) were chosen as model compounds to optimize the electrolytic conditions. As shown in Table 1, when constant current electrolysis (CCE) of 1a and 2a was performed in an undivided cell equipped with 0.1 M LiClO4 in CH3CN in the presence of AcOH using two graphite plates as anode and cathode, the

• ). Investigation of the anode proved that graphite was superior to Pt and DSA (Dimensionally Stable Anode, Table 1, entries 14 and 15). Finally, to further improve the reaction efficiency, several halide-containing mediators as redox catalyst were evaluated. To our delight, when n-Bu4NI was utilized as a redox

• coupling of N-arylglycine ester and C–H nucleophiles An undivided cell was equipped with a carbon anode (2 × 2 cm2) and a carbon cathode (2 × 2 cm2) and connected to a DC regulated power supply. To the cell was added N-arylglycine ester (0.5 mmol), C–H nucleophiles (0.6 mmol), n-Bu4NI (0.15 mmol) and 5 mL

The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives

• Shunsuke Kuribayashi,
• Tomoyuki Kurioka,
• Shinsuke Inagi,
• Ho-Jung Lu,
• Biing-Jiun Uang and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2018, 14, 389–396, doi:10.3762/bjoc.14.27

• oxidation of a substrate (1 mmol) was carried out in a plastic undivided cell equipped with platinum anode and cathode (2 cm × 2 cm) containing 10 mL of HF salt (20 equiv of F− to substrate/solvent) at room temperature. A constant current (40 mA) was passed until the starting material was mostly consumed

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• under a nitrogen atmosphere in dichloromethane solution on a graphite anode and a cathode of stainless steel at a constant current of 20 mA (Scheme 12). Depending on the cycloalkene used, the target vinylphosphonium salt was obtained in a yield of 53–66% [19]. Since the oxidation potential of

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

• Artur Jabłoński,
• Yannic Fritz,
• Hans-Achim Wagenknecht,
• Rafał Czerwieniec,
• Tytus Bernaś,
• Damian Trzybiński,
• Krzysztof Woźniak and
• Konrad Kowalski

Beilstein J. Org. Chem. 2017, 13, 2521–2534, doi:10.3762/bjoc.13.249

• the dye for 15 minutes. The imaging was performed using a LSM 780 confocal system (Zeiss), equipped with an AxioObserver Z1 inverted microscope, a 63× oil immersion objective (NA 1.4), a 355 nm DPSS laser (50 mW), a 561 nm DPSS laser (20 mW), and a multi-anode PMT (32 elements). The luminescence

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• anode material in lithium or sodium ion batteries. Experimental All chemicals were acquired from commercial sources (Acros or Sigma-Aldrich) and used without further purification. Synthesis and structural characterization: NMR spectroscopy was applied with a Bruker ARX 400 spectrometer. Fourier

1-Imidoalkylphosphonium salts with modulated C_α–P⁺ bond strength: synthesis and application as new active α-imidoalkylating agents

• Jakub Adamek,
• Roman Mazurkiewicz,
• Anna Węgrzyk and
• Karol Erfurt

Beilstein J. Org. Chem. 2017, 13, 1446–1455, doi:10.3762/bjoc.13.142

• . Decarboxylative α-methoxylation of 2-imidoalkanecarboxylic acids 6 to N-(1-methoxyalkyl)imides 7 [18]: To an undivided electrolyzer (100 cm3) with a thermostatic jacket equipped with a magnetic stirrer, a cylindrical Pt mesh anode (47 cm2) and cathode (44 cm2), methanol (30 cm3), 2-(N-imido)alkanecarboxylic acids